<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>动态背景登录组件</title>
    <style>
        * {
    margin: 0;
    padding: 0;
}

body {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(200deg, #e3c5eb, #a9c1ed);
    overflow: hidden;
}

.container {
    position: relative;
    z-index: 1;
    background-color: #fff;
    border-radius: 15px;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 350px;
    height: 500px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

.container .tit {
    font-size: 26px;
    margin: 65px auto 70px auto;
}

.container input {
    width: 280px;
    height: 30px;
    text-indent: 8px;
    border: none;
    border-bottom: 1px solid #ddd;
    outline: none;
    margin: 12px auto;
}

.container button {
    width: 280px;
    height: 40px;
    margin: 35px auto 40px auto;
    border: none;
    background: linear-gradient(-200deg, #fac0e7, #aac2ee);
    color: #fff;
    font-weight: bold;
    letter-spacing: 8px;
    border-radius: 10px;
    cursor: pointer;
    transition: 0.5s;
}

.container button:hover {
    background: linear-gradient(-200deg, #aac2ee, #fac0e7);
    background-position-x: -280px;
}

.container span {
    font-size: 14px;
}

.container a {
    color: plum;
    text-decoration: none;
}

ul li {
    position: absolute;
    border: 1px solid #fff;
    background-color: #fff;
    width: 30px;
    height: 30px;
    list-style: none;
    opacity: 0;
}

.square li {
    top: 40vh;
    left: 60vw;
    animation: square 10s linear infinite;
}

.square li:nth-child(2) {
    top: 80vh;
    left: 10vw;
    animation-delay: 2s;
}

.square li:nth-child(3) {
    top: 80vh;
    left: 85vw;
    animation-delay: 4s;
}

.square li:nth-child(4) {
    top: 10vh;
    left: 70vw;
    animation-delay: 6s;
}

.square li:nth-child(5) {
    top: 10vh;
    left: 10vw;
    animation-delay: 8s;
}

.circle li {
    bottom: 0;
    left: 15vw;
    animation: circle 10s linear infinite;
}

.circle li:nth-child(2) {
    left: 35vw;
    animation-delay: 2s;
}

.circle li:nth-child(3) {
    left: 55vw;
    animation-delay: 6s;
}

.circle li:nth-child(4) {
    left: 75vw;
    animation-delay: 4s;
}

.circle li:nth-child(5) {
    left: 90vw;
    animation-delay: 8s;
}

@keyframes square {
    0% {
        transform: scale(0) rotateY(0deg);
        opacity: 1;
    }

    100% {
        transform: scale(5) rotateY(1000deg);
        opacity: 0;
    }
}

@keyframes circle {
    0% {
        transform: scale(0) rotateY(0deg);
        opacity: 1;
        bottom: 0;
        border-radius: 0;
    }

    100% {
        transform: scale(5) rotateY(1000deg);
        opacity: 0;
        bottom: 90vh;
        border-radius: 50%;
    }
}
    </style>
    
</head>

<body>
    <div class="container">
        <div class="tit">登录</div>
        <input type="text" placeholder="账号">
        <input type="password" placeholder="密码">
        <button>登录</button>
        <span>没有账号？<a href="#">去注册</a></span>
    </div>
    <div class="square">
        <ul>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
        </ul>
    </div>
    <div class="circle">
        <ul>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
        </ul>
    </div>
</body>

</html>